Macromolecules, Vol.27, No.25, 7478-7485, 1994
Poly(Benzo(1,2-B4,5-B’)Dithiophene-4,8-Diylvinylene) - Synthesis, Properties, and Electronic-Structure of a New Dithiophene-Fused P-Phenylenevinylene Conducting Polymer
A new conducting polymer poly(benzo[1,2-b:4,5ib’]dithiophene-4,8-d (1), has been synthesized by the pyrolysis of the soluble precursor polymer 2, which was itself prepared by a multistep synthesis. The polymer is burgundy, and a film has lambda(max) = 503 nm (2.47 eV) and a band-gap (band edge) of 1.89 eV. Upon doping (FeCl3) the polymer film becomes light blue-green and has a conductivity of 60 S cm(-1). The original absorption peak at 503 nm decreases, while two new near-IR absorptions at 860 and 1860 nm appear during doping, which is reversible. Quantum mechanical calculations show a rather low rotational barrier in the monomer, and additional calculations on various oligomers and the polymer suggest that the stable form of the polymer is aromatic and planar.
Keywords:DIATOMIC DIFFERENTIAL-OVERLAP;LOW-BAND-GAP;PARTIAL RETENTION;VINYLENE);COPOLYMERS;BLENDS;FECL3